First day of the Great Patriotic War (June 22, 1941)

May 9th Victory Day is a big day in the Russian calendar and psyche. I was surprised though last week to see people in military uniform and band playing music by the local library when I was walking up the hill to pick up documents from the university.
The music didn't sound melancholy at all. This prompted me to ask a spectator what the occasion was. He explained it was to commemorate the start of the Great Patriotic War. (When Nazi Germany invaded the Soviet Union- "Operation Barbarossa" which involved 4.5 million troops marching across the border.) As the music sounded upbeat I was curious to ask if it was a happy or sad day. No, it was a sad day. I couldn't figure out why the upbeat music though. Cultural observations don't always come with ready made explanations.